Some image-forming devices well known in the art are configured of image-carrying members for carrying developer images, and a belt disposed in confrontation with the image-carrying members so that the image-carrying members transfer developer onto the belt or onto a recording medium conveyed along the belt. In this type of image-forming device, the belt is adjusted to an appropriate tension for performing the transfers.
Japanese Patent Publication No. 2000-305372 proposes a technique for setting the tension state of the belt in a halted state lower than the tension state during a transfer operation. With this construction, a tension suitable for a transfer operation is generated in the belt when the belt is driven to perform a transfer operation, thereby ensuring stable movement of the belt. On the other hand, when the belt is halted for a long period of time, the tension in the belt is reduced from that during a transfer operation to prevent the belt from becoming misshapen (stretching that lingers in the belt due to pressure being applied in specific areas of the belt over a long period of time).